Apparatus for the manufacture of molds for casting metals



United States Patent Inventor Horst Erwin Langer Augsburg, Germany Appl.No. 631,673 Filed April 18, 1967 Patented Dec. 1, 1970 AssigneeMaschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Augsburg, GermanyPriority April 21, 1966 Germany No. M69223 APPARATUS FOR THE MANUFACTUREOF MOLDS FOR CASTING METALS 3 Claims, 2 Drawing Figs.

US. Cl 164/203, 164/260; 259/1 Int. Cl B22c 15/10 Field of Search164/37, 39,

169,172, 203, 260, 206, 261;25/41(.1); 173/139; 259/1, (vibrators fluid)References Cited UNITED STATES PATENTS 2/1913 Holzapfel 164/169 5/1922Stevens 164/169 10/1934 Hepperle... 164/169 1/1935 Jackson..... 25/41JX5/1937 Ludeman 259/1 9/1940 Swarthout 259/1 9/1956 Fontainc 259/]Primary ExaminerJ. Spencer Overholser Assistant Examiner-John S. BrownAttorney-Woodhams, Blanchard and Flynn ABSTRACT: A vibrating apparatusadapted particularly for packing foundry sand compositions to make metalcasting molds in which the vibrator housing has a removable cap made ofa highly wear-resistant material and the vibrator housing is connectedby means of an elastomeric collar to a tubular connecter pipe and thetubular connecter pipe has a handle construction mounted thereon bymeans including an elastomeric sleeve.

APPARATUS FOR THE MANUFACTURE OF MOLDS FOR CASTING METALS This inventionrelates to a process for the manufacture of molds for casting metals inwhich the starting material em-. ployed consists of granular moldingsubstances, in particular for the fabrication of cores, the moldingsubstances being compacted by vibration after having been introducedinto the negative mold.

At the time of manufacture of molds, it is important to ensure that themolding substance completely fills the mold recesses (negative mold)formed by the pattern and foundryflask as well as the corebox, and thatthe sand or like molding substance has a compact texture, especially onthe outer mold face, in order that the liquid metal should not bepermitted to penetrate into the molding substance while casting is inprogress, that is to say in order to prevent the metallization of themold. For this purpose, the molding substance is either vibrated orrammed in accordance with known techniques, these operations beingperformed either by means of vibrators which are fixed outside themold-flask, or by means of vibratory rammers.

Vibrators of the external type do not ensure satisfactory distributionof the molding material. In fact, such devices are even whollyunsuitable for the purpose of making molds having tapered contours orpronounced recesses. On the other hand, when making use of vibratoryrammers, the molding material cannot be satisfactorily compacted unlessit is poured into the flask and rammed in successive layers. However,the highly tamped and compacted external surface cannot form an intimatebond with the contiguous layer which is poured thereon, with the resultthat there are thus formed virtual joints which are detrimental to thestrength of the mold. Furthermore, vibratory rammers are liable to causedirect damage to the mold surfaces of the pattern or the corebox whereasexternal vibrators can be employed only with metallic molds by reason ofthe high alternating stresses which they impart to the foundry-flasksand coreboxes.

The reasons explained above have led to the execution of the mold orcore in several sections, especially in the case of molds havingcomplicated and substantially tapering contours. In such cases, themolding material must be introduced, spread and tamped by hand withinthe different portions of the negative mold. This operation evidentlydemands a substantial amount oftime.

The object of the present invention is to reduce to an appreciableextent the expenditure of energy and labor required in the fabricationof molds and mold elements (e.g. cores) of the type mentioned above andto improve the quality of the mold texture without any risk of damage tothe pattern.

This object is achieved by means of the method according to theinvention which consists in making use of molding substances having asufficient fluidity which are distributed and compressed by means of aninternal vibrator. It is possible to employ as molding substances allthe solidification sands with or without iron oxide, cold resin sands,cement sands and the lor the vibrating operation, it has provedparticularly advantageous to make use of the so-called poker vibratorswhich are attached to a handle by means ofa flexible member and can beoperated after the fashion ofa trowel for the purpose of distributingthe molding substance. An unexpected feature which has been found inpractice is that these poker vibrators are not subject to excessivewear, even when the packed molding sands contain a very high proportionof quartz sand which is on an average considerably higher than isnormally present in concrete structures. Wear develops almost entirelyat the lower end of the vibratory poker, the end portion beingadvantageously removable and interchangeable for this reason.

One example of embodiment of an internal vibrator for the practicalapplication of the method according to the invention is describedhereinafter, reference being made to the accompanying drawings, inwhich:

FIG. I is a fragmentary side elevation view of an internal vibrator ofthe pneumatic drive type.

FIG. 2 is a transverse sectional view taken along the line [H] of FIG.1.

The vibratory poker l is of the pneumatic drive type in the exampleunder consideration but can operate equally well either by hydraulic orelectric means. The poker is provided at its lower end with a removablescrewcap la formed of material which affords high resistance to wear andis surrounded by a sleeve 2. Said sleeve is fitted over a rubber collar3 in which is inserted a tubular connecter pipe 4. A rotatable handle 5is fixed to the upper end of the connecter pipe and it is possible byactuating said handle either to start or stop the vibrator, that is tosay to open or close the compressed-air intake, compressed air beingsupplied through a hose which is connected at 6. The compressed airpasses into the vibrator through an inner tube 7 and is discharged tothe outside air through the annular passageway 8 between the tube 7 andthe connecter pipe 4 and through discharge apertures 9. In order to makethe machine easier to handle, provision is made at the upper end of theconnecter pipe for a flexible tubular handle 10 which is strengthened bya sheet metal sleeve 11. The connecter pipe 4 can be employed at thesame time for the attachment of a lamp 12, in particular when themachine is used in molds of substantial depth.

The apparatus which has just been described therefore constitutes atrowel, the lower end of which works as a vibrator, so that theapparatus can be directed as required by the operator, contradistinctionto poker vibrators of the known types which are employed, for example,in concrete construction work.

Iclaim:

l. A vibration apparatus for packing foundry sand compositions to makemetal casting molds, comprising:

an elongated housing having a removable cap made of highlywear-resistant material removably secured to one end of said housingwhereby said cap may contact the material to be vibrated;

vibrating-causing means disposed within said housing and adapted toimpart vibrations thereto;

a handle construction spaced from and connected to other end of saidhousing; and

coupling means connecting said handle construction to said other end ofsaid housing (1) for permitting transverse or lateral motions applied tosaid handle construction to be transmitted to said housing and (2) forsubstantially preventing transmission of vibrations from said housing tosaid handle construction, said coupling means including:

a. an elastomeric sleeve mounted within the housing adjacent said otherend thereof;

b. a tubular connecter pipe of rigid material received within andattached to said elastomeric sleeve and extending outwardly from saidother end of said housing whereby the vibrations of the housing aresubstantially absorbed by the elastomeric sleeve and are notsubstantially transmitted to the rigid connecter pipe; and

c. an elastic sleeve encircling and secured to said rigid connecter pipeadjacent the outer end thereof, said the elastic sleeve being surroundedby and connected to aportion'of said handle construction forinterconnecting said handle construction to said housing.

2. A vibration apparatus according to claim 1, including a furthertubular pipe disposed within said connecter pipe and extending betweensaid housing and said handle construction, said further tubular pipebeing smaller than said connecter pipe to define a first flow passagewaywithin said tubular pipe and a second flow passageway within saidconnecter pipe in surrounding relationship to said further tubular pipe,said passageways being used to provide for flow of pressure fluid to andfrom the housing.

3. A vibration apparatus according to claim 1, including a bracketattached to the connecter pipe between the housing and the handleconstruction and extending sidewardly therefrom, and a lamp mounted onsaid bracket and extending toward said one end of the housing forilluminating the materi al being vibrated.

